Integrative genomic analysis for the functional roles of ITPKC in bone mineral density

Osteoporosis is defined by low bone mineral density (BMD), which is mainly due to the imbalances in osteoclast and osteoblast activity. Previous studies indicated that early activation of osteoclasts relies on calcium entry through store-operated calcium (SOC) entry, and several genes, including STIM1, ORAI1, and ITPKC, are known as key regulators of SOC entry. However, the relationships between STIM1, ORAI1, ITPKC, and human BMD are still unclear. In order to investigate the plausible associations between these genes and BMD, we conducted a meta-analysis of genes expression and BMD using the publicly available GEO database. We further recruited 1044 subjects and tested associations between polymorphisms in these genes and BMD. Clinical information (including age, sex, and BMI) was collected and used for the analysis. Our results indicated that ITPKC gene expression was significantly associated with BMD. Furthermore, we found that one ITPKC SNP (rs2607420) was significantly associated with lumbar spine BMD. Through bioinformatics analysis, rs2607420 was found to be very likely to participate in the regulation of ITPKC expression. Our findings suggest that ITPKC is a susceptibility gene for BMD, and rs2607420 may play an important role in the regulation of this gene.